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TROPICAL STORM DALILA DISCUSSION NUMBER 7
NATIONAL WEATHER SERVICE MIAMI FL
8 AM PDT SUN JUL 22 2001
ON SATELLITE IMAGES...THERE HAS BEEN LITTLE CHANGE IN THE
ORGANIZATION OF THE SYSTEM OVER THE PAST SEVERAL HOURS...WITH NOT
MUCH EVIDENCE OF BANDING FEATURES. DVORAK INTENSITY ESTIMATES FROM
TAFB AND SAB ARE JUST BELOW HURRICANE STRENGTH...AND THE AIR FORCE
WEATHER AGENCY ESTIMATE IS A LITTLE LOWER. EVEN WITH THE FIRST FEW
VISIBLE IMAGES...IT IS DIFFICULT TO DETERMINE HOW FAR THE CENTER IS
EMBEDDED IN THE DEEP CONVECTION...AND THUS HOW STRONG THE SYSTEM IS.
WATER VAPOR WINDS SUGGEST SOME EASTERLY SHEAR OVER THE AREA...WHICH
COULD INHIBIT STRENGTHENING. HOWEVER AT THIS TIME IT IS ASSUMED
THAT DALILA WILL BE ABLE TO OVERCOME THE SHEAR AND STRENGTHEN TO
NEAR CATEGORY 2 HURRICANE STATUS. THE OFFICIAL INTENSITY FORECAST
IS THE SAME AS THE PREVIOUS ONE...AND SIMILAR TO THE SHIPS GUIDANCE.
INITIAL MOTION ESTIMATE REMAINS 295/13. THE GLOBAL MODELS MAINTAIN
A MID-TROPOSPHERIC RIDGE TO THE NORTH OF THE TROPICAL CYCLONE OVER
THE NEXT FEW DAYS. THIS SHOULD KEEP DALILA FROM GETTING MUCH CLOSER
TO THE COAST. THE GFDL AND NOGAPS MODEL SHOW A TURN TOWARD THE BAJA
PENINSULA NEAR THE END OF THE FORECAST PERIOD. HOWEVER BASED ON THE
SYNOPTIC FLOW AND THE OTHER TRACK GUIDANCE WHICH IS FAIRLY TIGHTLY
CLUSTERED...THE OFFICIAL FORECAST MAINTAINS THE WEST- NORTHWEST
MOTION THROUGH THE PERIOD. NONETHELESS...ONLY A SMALL DEPARTURE OF
THE TRACK TO THE RIGHT WOULD BRING STRONG WINDS AND HEAVY RAINS TO
THE COAST.
FORECASTER PASCH
FORECAST POSITIONS AND MAX WINDS
INITIAL 22/1500Z 15.3N 101.3W 60 KTS
12HR VT 23/0000Z 16.0N 103.1W 65 KTS
24HR VT 23/1200Z 16.9N 105.1W 70 KTS
36HR VT 24/0000Z 17.8N 107.0W 80 KTS
48HR VT 24/1200Z 18.5N 108.5W 85 KTS
72HR VT 25/1200Z 20.0N 111.5W 85 KTS
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